netlabel: cleanup struct netlbl_lsm_catmap

Simplify the code from macro NETLBL_CATMAP_MAPTYPE to u64, and fix
warning "Macros with complex values should be enclosed in parentheses"
on "#define NETLBL_CATMAP_BIT (NETLBL_CATMAP_MAPTYPE)0x01", which is
modified to "#define NETLBL_CATMAP_BIT ((u64)0x01)".

Signed-off-by: George Guo <guodongtai@kylinos.cn>
Acked-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: David S. Miller <davem@davemloft.net>